Hob grinding machine



Aug. 30, 1932. 3,5, OLSON 1,874,592

nos ennwmc ucnms Filed m. s. 1929 5 Sheets-Sheet 1 kg g j /ZZO (517/0Z5? Aug; 30, 1932' c. e, OLSON HOB GRINDING CHINE 5 SheetsSheet 2 :"L 6w A D 1 Filed Juno '8. 1929 Aug. 30, 1932. c. a; OLSON 2 nos 9123mmIAGHINE I Filed June 8. 1925 5 Sheets-Sheet 3 Aug. 30, 1932. c. e.transom 1,374,592

nos enmnme lucamrz Filed Juno 8. 1929 5 Sheets-Sheet '5 Patented Aug.30, 1932 UNITED STATES PATENT OFFICE CARL G. OLSON, OF CHICAGO,ILLINOIS, ASSIGNOR TO ILLINOIS TOOL WORKS, OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS HOB GRINDING MACHINE Application filed June 8,1929. Serial No. 369,502.

My present invention relates to improvements in methods of an apparatusfor grinding hobs and it is one of the primary objects provision ofmethods and apparatus whereby grinding operations on a hob may be performed without the ,necessity of using a plurality of machines andwithout the necessity of adjusting the grinding wheels for eachoperation and to this end I propose to successively position each of thevarious grinding wheels in substantially the same operating zone andupon the same mounting. More specifically, it is an object of my presentinvention to provide improved grinding wheel supporting means inassociation with a rotatable hob supporting spindle, said grinding wheelsupporting means being such as to'enable grinding wheels used forsuccessive and different grinding operations to be very accuratelypositioned with a minimum amount of eiiort and skill on the part of theoperator.

Another object of my present invention is to provide in combination witha reciprocable grinding tool support, adjusting means of improvedpractical construction whereby the degree of reciprocating movementexperienced by the grinding tool support may be accurately and quicklyadjusted.

More specifically, my invention contemplates the provision of a strokeadjusting device in which a rack and pinion mechanism is employed toadjust the pivotal point of the link interposed between an actuatingcam" and the cross slide or carriage.

These and numerous other objects and advantages will be more apparentwhen considered in connection with the accompanying drawings, wherein:

Figure 1 is a side elevational view shown partly in cross section of ahob grinding machine which is representative of a grinding machine bymeans of which my improved method of grinding hobs may be efficientlypracticed;

Figure 2 is an end view of the machine as viewed from the right ofFigure 1.

Figure 3 is a plan view of that portion ofthe machine which supports thehob and the grinding wheel;

Figure 4 is an enlarged fragmentary transverse sectional view of themachine taken substantially along the line 4-4 of Figure 1;

Figure 5 is a detailed plan sectional view taken substantially along theline 5-5 of Figure 4;

Figure 6 is an enlarged fragmentary elevational view disclosing themanner in which a grinding wheel may be employed to grind the outerrelieved surfaces of the hob teeth;

Figure 7 is a fragmentary elevational view disclosing the manner inwhich a grinding wheel may be employed to grind spline hobs and thelike; i

Figure 8 is an end view of the grinding fixture as viewed from the rightof Figure 6;

Figure 9 is a horizontal fragmentary sectional view taken substantiallyalong the line 99 of Figure 7;

Figures 10 and 11 are fragmentary plan I views disclosing the manner .inwhich grindv in wheels may be emplo ed for grinding at relieved sidesurfaces if the hob teeth; andv Figures 12 and 13 are front or sideelevational views of the grinding wheels and supports shown in Figures10 and 11, the hob 1n each instance being shown by dot and dash lines inorder to disclose the parts which would otherwise be hidden.

Referring now to the drawings more in detail wherein like numerals havebeen employed to designate similar parts throughout the various figures,it will be observed that for the purpose of illustrating one practicalapplication of my invention I have disclosed a hob grinding machine, thespindle driving mechanism of which simulates that disclossd in the IrwinPatent No. 1,70%,833, and my Patent No. 1,667,488. This drivingmechanism includes an integral spindle 20, one extremity thereof beingdesigned for supporting a hob 22 and. the other extremity thereof beingformed so as to present a lead screw 24. The spindle 20 is mountedbetween a bearing 26 and a bearing 28, the latter bearing providing anut in which the lead screw 24 rotates. The spindle 20 carries a gear 30which meshes with an elongated pinion 32 .andthis pinion 32 is driventhrough the that therotation of the lead screw 24 within the hearing ornut 28 will cause the hob to be moved axially, the lead of the screw 24being equal to the lead of the thread in the hob. It will be noted inFigures 1 and 3 that the hob is shown in its retracted position, thatis,

in its extreme left position, Figure 1, and

this position is shown merely for the purpose of more clearly bringingto view the grinder unit which I have designated generally in Figures 1to 3 inclusive by the numeral 42.

This grinder unit 42 comprises a grinding wheel 44 which is designed togrind the relieved-outer surfaces of the hob teeth, said grinder wheelbeing mounted upon a spindle 46 which is rotatable within a bearing 48.The outer end of the spindle 46 is provided with a pulley 50 which isconnected in any suitable manner such as by means of a flexible belt 52to a source of power supply (not shown). The bearing 48 is supportedupon a base plate 54 which is centrally split at 56, Figure 8, so as toenable said base to be clamped upon a mounting 58. The base 54 isadapted to be clamped in position upon the mounting 58 by means of asuitable handle 60 which is mounted at the threaded ex- 'tremity of aclamping bolt 62 which completely traverses the base 54. In thisconnection it is to be noted that the base 54 is positioned upon themounting 58 so as to accurately position the grinding wheel 44 withrespect to the hob. In other words, the dovetailed connection betweenthe mounting 58 and the base 54 serves to insure the accuratepositioning of the grinding wheel with a minimum amount of effort on thepart of an operator. The mounting 58 is carried by a slide 64, themovement of said slide being controlled by a hand wheel 66 which iscarried by and secured to a screw 68. This slide 64 is in turn carriedupon a slide 7 0 which is movable transversely of the machine by meansof'an operating handle 72 carried by a screw 74,Figure 4. It will thusbe apparent that the grinder unit 42 may be moved axially of the hobspindle by manipulating the handle wheel 66 and may be movedtransversely of the spindle axis by rotating the handle 7 2. a The slide7 0 is mounted upon a carriage 7 6 which is horizontally reciprocableupon a sub-base 7 8. Reciprocation is imparted to the carriage 7 6through the agency of a cam 80, Figures 1, 2, 4 and 5, which is thenumeral 88. A link which includes 2. pair of spaced arms 92 is pivotallysecured at one extremity to the lower end of a depending arm 94 which isformed integral with or' otherwise secured to the carriage 76. Theopposite extremity of the arms 92 receive a shaft 96, the portion of theshaft passing through the frame or yoke 86 supporting a collar 98. Thiscollar 98 snugly fits within the longitudinal opening of the frame 86and thus forms a connecting bearing between the frame 86 and the link90. A coil spring 100 is interposed between one wall of the sub-frame 78and a pin 102 secured to the carriage 76 and this coil spring serves toconstantly urge the carriage to the right, Figure 4. From the foregoingit will be understood that during each rotation of the cam 80, the frame86 will experience one complete oscillation and the carriage 76 acomplete reciprocation. In order to vary the position of the shaft 96within the frame so as to enable variations in the stroke imparted bythe cam 80, I provide a rack and pinion device which includes a rack bar104 and a companion pinion 106 which is secured to the shaft 96. Thus,rotation imparted to the pinion 106 will cause the shaft 96 t0 beraisedor lowered with respect to the ,pivotal point 88, thereby varying thestroke imparted to the link 90. In order to facilitatethe rotation ofthe shaft 96 I provide a suitable hand wheel 108. To secure the shaft 96in its various positions of adjustment I provide a ratchet 110 which issecured to the shaft 96 and the teeth of this ratchet are adapted to beengaged by a yield- ,able pawl or pin 112. This pin 112 is continuouslyurged into engagement with the teeth of the ratchet 110 by means of asuitable spring 114 mounted within a housing 116 which is carried by thelink 90. The resiliency of the spring114 is such as to yield in responseto manual manipulation of the hand wheel 108 and thus a convenientarrangement is provided for rendering the position of the shaft 96adjustable at all times.

The inner end of the cam shaft 82 is connected with a drive shaft 116through the agency of a click-clutch mechanism desig- 8 nated generallyby the numeral 118. This clutch mechanism is similar in operatingcharacteristics to that disclosed in the patent to Olsen et al. ReissueNo. 16,590, and therefore a detailed explanation of the constituentparts will not be given at this time. It will suflice to say that thisclutch mechanism includes a pair of ratchet members 120 and 122, thefunction thereof being to permit the member 120 to rotate backwardwithout rotating the companion member or section 122. In this way theposition of the cam is never disturbed when the hob is returned for asuccessive grinding operation. which rotates the clutch member 120, isdriven from the shaft of the pinion 86 through the agency of a train ofgears 124:, 126 and 128, Figure 1. The sub-frame 78 which supports thecam shaft and its associated mechanisms, rests upon a main frame 130which houses the driving mechanism, etc., (not shown).

Thus far, the description of the grindingwheels has been limited to thespecific type of wheel shown in Figure 6 and in Figures 1 to 3inclusive. This grinding wheel 44 is particularly adapted for grindingthe outer relieved surfaces of the hob teeth. In order to performanother grinding operation upon the hob teeth it is only necessary toimpart a loosening twist to the handle 60 and slide the unit 42 from themounting 58 and replace said unit by another unit as for example one ofthe units shown in Figures 10 and 11 which are designated generally bythe numeral 42a. Each of these units 42a includes a grinding wheel 44amounted upon a spindle 460, which is rotatable within a bearing 48a. Abase 54a supports the bearing 48a and it will be apparent that one ofthe grinding Wheels will serve to grind one side of the hob teeth andthe other wheel will grind the opposite side. Each of the bases 54a areadapted to be clamped in position upon the mounting 58ain the samemanner as the base 54 by merely manipulating a hand wheel 60a.

In Figures 7 and 9 I have disclosed still another grinding unit which Ihave designa-ted generally by the numeral 42?). This grinding unitincludes a grinding wheel 44?) which is of the type adapted for grindingspline hobs and the like. The wheel 4A?) is carried by a suitablespindle 46?) mounted within a bearing 48?). This bearing is mounted upona base 54?) which is similar in construction to the base 5.4 alreadydescribed. 'A suitable handle is provided to effect the clamping of thebase 54?) upon the mounting 58.

From the foregoing it will be apparent that my invention enables asuccession of grinding operations to be performed in a very convenientand economical manner. By practicing my improved method of grindinghobs, a grinding wheel, as for ex- The shaft 116 ample the grindingwheel 44, is supported ina predetermined position and by suitablerotation of the hob and the wheel, the outer surfaces of the hob teethare relieved. Upon the completion of this grinding operation thisgrinding wheel is removed and a grinding wheel for performing adifferent grinding operation is supported similarly to the firstmentioned wheel without disturbing the position of the hob, and thenthis second wheel is operatively associated for grinding the hob teethas for example the relieved sides of the teeth by the use of thegrinding wheels 44a. Obviously, various types of wheels may be employedfor producing diiferent grinding operations upon the teeth. The standardmounting 58 serves as a common support for all of the grinding units,the grinding wheels being thus successively positioned in substantiallythe same grinding zone for each operation. Each of the grinding wheelsand their respective spindles must be positioned at the proper elevationin order to properly function and this proper vertical positioning ofthe wheels is accomplished by aving the unit so arranged that thedistance between the spindle axis and the top of the mounting 58 is inaccordance with the design of the hob to be ground. It will be apparentthat by successively positioning grinding wheels in the same zone ofaction in the manner described, a minimum amount of adjustment of thegrinding wheel is necessitated. In some of the methods which haveheretofore been practiced in performing the 1913 various grindingoperations to which a hob must necessarily be subjected, numerousadjustments have been made to properly position the grinding wheel andthese adjustments have not only necessitatedv consider- 105 able skillon the part of the operator but also have required the expenditure of aconsiderable amount of time. By using my improved apparatus inpracticing the above described method, I am able to reduce the necessityfor adjusting the position of the grinding wheels to a minimum by reasonof the simplicity in successively mounting said wheels in operativerelation with respect to the hob teeth. The described means for ad- 5justing the stroke of the transverse carriage 76 also presents a simpleand economical construction. By merely imparting rotation to the handwheel 108 the axis of the shaft 96 may be raised or lowered with respectto the pivotal point 88 so as to adjustably control the degree of reliefwhich is imparted to the hob teeth during the grinding operations. Thedescribed apparatus presents a very compact, efliciently operablemachine which may be economically manufactured.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is: I

1. The method of grinding hobs having a spiral series of relieved teethwhich includes the steps of supporting a grinding wheel in apredetermined position, rotating the grinding wheel and the hob toeifect a certain grinding operation on one of the surfaces of the hobteeth, removing said grinding wheel upon the completion of said grindingoperation, maintaining the position of the hob and similarly supportinganother grinding wheel for grinding a second surface of the hob teeth,effecting grinding contact between the hob and the second mentionedwheel, replacing said second mentioned wheel with a third wheel, andefi'ecting grinding contact of said Wheel with a third surface portion.a

2. In a machine of the class described, a

rotary work supporting spindle, a tool hold-' to the axis of oscillationof the oscillatory means.

3. In a machine of the class described, a rotary work supportingspindle, a tool holder for supporting a tool in operative position withrespect to said work, and means for causing relative bodily movementbetween the work and the tool radially of the work axis, said meansincluding a cam and an oscillatory means for imparting movement to oneof the aforementioned parts, said oscillatory means having a connectingmember and a rack and pinion mechanism for effecting the adjustment ofsaid connecting member with respect to the axis of the oscillatory meanswhereby movements imparted in response to the actuation of the cam maybe ad- 1 justably varied.

4. In a machine of the class described, a roe tary work supportingspindle, a tool holder for supporting a tool in operative position withrespect to the spindle, said tool holder being reciprocable to effectthe movement of the tool radially of the work carried by the spindle,and means for reciprocating said tool holder including a cam, anoscillatory means engaging said cam, and means for operativelyconnecting said oscillatory means with the work holder, said oscillatorymeans having a connecting member mounted therein which is adapted to beadjustably positioned with respect to the axis of said oscillatory meanswhereby variations in the stroke imparted to the tool holder in responseto the actuation of the cam may be adjustably varied.

5. In a machine of the class described, a rotary work supportingspindle, a. tool holder for supporting a tool in operative position withrespect to the work, and means for imparting relative bodily movementbetween the work and the tool including a rotary cam, and an oscillatoryframe engaging said cam for imparting movement to one of theaforementioned parts in response to the rotation of the cam, aconnecting member within said frame, and a rackand pinion mechanismassociated with said frame for adjusting the position of said connectingmember with respect to the axis of oscillation of the frame.

6. In a machine of the class described, a rotary work supportingspindle, a tool holder for supporting a tool in operative position withrespect to the work, and means for imparting relative bodily movementbetween the work and the tool including a rotary cam, an oscillatoryframe engaging said cam for imparting movement to one of theaforementioned parts in response to the rotation of the cam, aconnecting member within said frame, a rack and pinion mechanismassociated with said frame for adjusting the position of said connectingmember with respect to the axis of oscillation of the frame, and meansfor locking the rack and pinion mechanism in various positions ofadjustment.

7. In a machine of the class described, a rotary work supportingspindle, a tool holder for supporting a tool in operative position withrespect to the work, and means for imparting relative bodily movementbetween the. work and the tool including a rotary cam, an oscillatoryframe engaging said cam for imparting movement to one of theaforementioned parts in response to the rotation of the cam, aconnecting member within said frame, a rack and pinion mechanismassociated with said frame for adjusting the position of said connectingmember with respect to the axis of oscillation of the frame, and a pawl'and ratchet mechanism securing said rack and pinion mechanism in variouspositions of adjust'ment.

8. In a hob grinding machine of the class described, a rotary worksupporting spindle, means for effecting longitudinal movement of thespindle, a tool holder for supporting a grinding wheel in operativeposition with respect to the work supported by the'spindle during therotary and longitudinal movement thereof, a machine frame for slidablysupporting the grinding wheel holder, a rotary cam, a pivoted memberengaging said cam, means connecting said pivoted means with the grindingwheel holder, and a rack and pinion mechanism for varying the positionof said connecting means to adjustably control the relieving action ofthe supported grinding wheel.

In witness whereof, I have hereunto subscribed my name.

I CARL o. OLSON.

